Mentor graphics calibre DRC error

[sg0786]

I am new to MG calibre tool. I was trying to do a DRC for simple NAND standard cell. In calibre RVE it throws error check GC.C.1
GC.C.1: GC Coverage less than 0.14 ( GC.C.1 ).

I was hoping that i should get a clean run for std cell in a library. what is this GC coverage error?

thanks

 

[slizak]

That looks like it is a DRC check. The DRC checks are coded in the SVRF rule file, which is usually provided by the foundry as part of the PDK. If this is a pre-existing standard cell that you expected to be clean, check that you are running the correct files for your process -- each process has different parameters for things like minimum width, coverage, and so on.

As for exactly what the check means, either look at the PDK for rule GC.C.1 or search the SVRF file for the code. The error statement is generic enough I can't tell whether the issue is a via is not being covered with enough margin, the density is too sparse for manufacture (that is, it would need fill), or some other check of relative placements.

-Sam.